Last night I designed a fast colonizer with a "prototype hyper drive" (it needs 1 promethium)

building this ship subtracts 1 promethium from my stack of 1 for the duration of the build process.

But why am I unable to put any build order using promethium (same or different ship) later in the same shipyard's queue?  The engine is unable to grasp that the stack will again contain promethium later, when that ship is no longer being constructed - it prevents me from queueing anything else  later that need promethium...?

Sorry If I missed any info about these resources (didn't have time to follow the forums or play the latest betas for some time...) and this behavior is in fact intentional, i.e. promethium is not *just* used to build it, but needed continually (as fuel?), too -- in this case please update the description of that prototype drive, as this fact is not entirely clear...!  It must be obvious if promethium is just needed to build the ship, or later to use that drive, too!

...but even then, the following variant of the above still is a bug that needs fixing...:

If I decide to try the "loop" function telling the shipyard "continue to make this design until further notice" more ships *will* be build continually, taking my stack into negative numbers -- which should not be possible...?!